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THE RELEASE OF ••£•',"DISPERSED ASBESTOSFIBRES FROM SOILS

. J Addison

.LST,v'Daykis ^A Robertson

Septemter

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J Addison, LST Daivies, A•:Robertson,.i

', SUMMARY

.Both natural and industrial asbestos contamination in soil on shes required fordevelopment can present'.health" hazards if: the. soil -is "to 1» b^turbed.v Very little".; 5;.vinformation is available about:^HkeIyJ''airb^rMvxisbestDS. fibre;;" concentrations which ;: ,might be: encountered; in, wor^gTsuch- a site 6r;on the possible" suppressant effectsof .water spraying during""work.1 ••.:','VvThis'study is aimed ' at providing some basicrelevant information to these problems. . . - . • , • > . - . " '

Artificial mixtures were prepared .using three'''different sb3 types (day, sand and "" :."'^>r; '^w1intermediate) with each of three asbestos types (chrysptile,"'_; arhosite and crbcidolite)in concentrations of 1%, 0.1%, 0.01% and 0.001%, by weight.; , ; ;

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Airborne dust clouds .were generated'•'over'. period^ of' four^hburs.; from each: "mixture' ;' ^.'l^.^^f.using: a dust. dispenser discharging into a 1.3;~:m3 ;test; chamber^;•',•'. Airborne dust ";tv--vAtfl^^-^concentratibns- .were rneasured .; for;'me. fidl^ duratjon^of^.me:;te^v^^-dust;:;';' sampling'.' mstrusnents; "^and'^ a i ;'isequence • .^c^fi xn^tt^&fi^ ^r-i-^^-.v.- •-••••^iS^f,

• coDec^i'. for; fibre ^coimidng' b^^i.concentrafeiB'^were.^de^

• ;iwere-: compared"TMAj,.,- -«%m-;.;•••.:.. . • -•-.. - -•

'- concentration: related to"cbnim6¥""bccupa^mg m~3. ; . -Parallel'/tests vi^OT^ca^eil^ <

j from: each mixture ^m^pit>gressivet:coh-•'concentrations "measured''over^ffii^^ume./periods.?alFtef^inrfiarr(^t:/'ciolaSf^generafion?

were used: to compare &e elfiectt;b^"the addition,of •»-+-- *«+K- —5^" ?- -ri- - • '

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generated.. " : • •• - • ~-- -•• - v -v - -

The results showed that airbbrne fibre ;c^^ml"1) and even : OT001% of.;'asbestos-"in^ii'- chyv^kiose^inErturel

...-:. ...'.' - ^ • • - - - .....-^' •-.-.,-» - • • - • - ' • , . . :. ••••'••••*•-t,^ ; •=i<v :"-"'- f -%-.-.-.:- ;.»-.-;-:" '•'•""'- r- i.'."::/- .;-.-;; ! ... "1* --•-; producing /airborne, respirable ' asbestos, concentrations --.uir, excess'clearance fimit;^ while'- at the - s^ime;:'time ' the :respirable.bekjw the nuisance dust OEL of' 5..mg" m~3';^ : :The naajor, cpritroinrig;4;fiictprjjon,,

' " " ' "" ' " 'tne."mlxtnr»^altho1ugnT;me;v-.-•-»'-. .-.••fl.-,^^.-n" ..-'.a- • rV'-....-....;. .. - ~ • . • • - • .;.'-;. .: • • .y. r-. -^~ . --^ • ...' *r—"-.~";V jet"--"'"" '''' "'' '--" ^i* T' • •~''^-^-'>J'^-g.^-.- • ,. '-^~ TTTnature of the sou and the asbestos type had -some influence." ror/ example, loose

• . - - . : : • •': • - •-:. • ;* . . - • - -r. . :'- . -<•: ...•--..'.* • ' » ' • - „ -• y .•-,•-•'-: i--v* *•-. -.'r : -^<^---. -.•"' .-:.-.;' '-.-' ^sr-'j:-^vZ>V :-'..J t'_ .'-••...•-.v ^^.;->^.' isanoy soils and.- soils containing amphibole- asbestos" tenoed tOvprpunce'mgQer nore-.^conceutran'ons (when disturbedT ithan "^^clay 'soils {or: .soils 'wim^chiTiodlei "v;; The - Vconcentran'ons (when disturbed) '--ithan,\^clay.addition of water to the "soils greatiyredik^t^

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"'%.'*•• "* '?-'"^5^'i:.~'r^''....':£.''S'f-'V/JVi>T4J':-.v".;;. 1. INTRODUCTION •.*r*;

Asbestos contamination can occur both .naturally, and as a result of -man's activities .on- ates"such::as- shipbreakers' yards,'- asbestos factories and waste tips. v ; 'Depending

Jon circumstances,' - the- asbestos may; simply lie: ;on ; the surface; of the . toil,.- it c mayhave been, buried in .pits or it may be -ultimately mixed- with the soil' and present";:to a considerable depth".;.'' : ''""Vy .'••':-.'•'• • • ' • " • •'''.:v°'-s'"'1. • • • •• ' •• "• ' • " ' •'•• - . • - . . . • " ' ';;;

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The potential hazards associated with disturbing grossly contaminated soils are.obvious but those associated with soil contaminated with trace amounts of: asbestos ';are unknown. ' Mesotheliomas in Cyprus -and. Turkey have .been attributed to^environmental. .. exposure \ to asbestos or asbestiform .. minerals present": m - . the i;soir';;.(Baris 'et'-'ai:,; 1982; / -McConnochie el a/,; 1987). The extent of the contamination Oin "these!, situations has iot: been -quantified birt it has .been shown that othermaterials contaminated by trace quantities of asbestos can produce relatively high'-.airborne concentrations' of asbestos fibres in dust clouds where, 'dust massconcentrations, are ;; low:. e.g.;. vermicidite ;and tremolste (Addison aid": Jones;, i-;. in.preparation):'' .'^'•.;.t':'o-k-'^-;'"-''-S''.^';^.'V:^'-'--V:^ .'.. '- •• ^• -" • • • • ' . i - '-'•;:•:.•;•' :'v.--=-k?'

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• *w-. -.'.TS

No fixedVsafelimit is givenby^ the: Department^of the Environment regarding, theasbestos, content of soils before; redevelopment can .take place. They .recommendthat if -fragments, of/asbestos; are visible on the: surface some act^/S£:njt^ed;.;5:butwhen only; instrumental : techniques can detect'''.' asbestos; ; /careful -'^ cbnsideratipn*. is

itiie.site is so cbritammitedithat.acti1985). J , - . . It is: clear that furrner/;gu«iance.T.is

necessarj:?4v;j'.;:?pne::!rap^frMch;'tO;;';'the., problem is to hisist that before ^reb^velopment^'.takes^ p^e^^^soa.:,must;;;te^free;;of: asbestos." /;;.vHowevef,. eviim.y-t^^p^jrMcir:ire^uires; "further'clarification as .the .clearance of a - site .using this;i criterion wilT-depend :on,: me sensitivii^/6f;.vth~e.v;'analytical7'niethodcontent ;^^tiie/spil;/j^The .'sensitiyities^of''. therange from• around 6.0001% to around/1%.: \.contaminated "soils • are /unknown it would be /desirablethe. most.;sensitive technique. Unfortunately, past experience has shown; that

great practical difficulties in obtaining site clearance:: andof reducing .risks to health. are unknown. : '},:On . the^:bther?

•- is not sufficiently sensitive substantial hazards

-.••-••*•:•--.••.-vv:.': -^V:

realV1 benefits :

There is , therefore: ' a clear need for information to assist in estabiishing .levels ;; ofasbestos 'contamination in soils at which action should be taken to reduce risksfrom , exposure "to airborne asbestos.

• ' ' ' / ' ' • ' . • • . • '•.'"•>'•' ".!.•" ..'".,- -•• • ' . . • ' . ' . . ; : • • ' ' • " • • • .:"•'' •'•. . ' ' ' : - - • ' • ' ' . ' •'-.: ' . •-In; addition, it is known that airborne fibre concentrations generated; during theremoval of asbestos m to 1000 by the'adop^onX'^-'/propd"''::;-'imttteg.,''pio and. Black, to be published).Although" no ••work-- has been / reported to date" on similar effects in toils, the

, addition ; of : water to" asbestos contaminated .soils ~ inay be an . impoitant controlmechanism m the suppression of airborne; asbestos ; ''fibres hi iworkinj environments.

This report describes preliminary investigations ' - into the relationships betweenasbestos, fibre- rekase from soils and . the asbestos .,' type and content, the iofl .••type--'

"and '"the ". soil moisture content. A. series of artificial mixtures, of aoil and asbestosha-^e been' used Ln the stixiv •whose three main aims wcrt to

the;; work^ on •; soil moisture; cbntent/amli dust; suppresibn

' * ' • ' • '" " • .''. . ' ' ' . ' ' - • -.-"«*- - • . "LVI- •' - A '•"* '•"" •• : . ' < • • • . ' " . ' ' . ' . . . - . - • . _ , ' • , , •

. , • ' . ' . . . ' 2. MATERIALS AND METHODS . . . . /•:;••»•,•.„,.• ;.±&.

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.;// 2.1.- •'•'-.Soils /' : • • -• • ' ' • ' • • • " ' : : £'•''.'•'/ . . . • • ' . . • • ' ' ' ' • . . • • ' . . ' • &v

,; ." /Three different soil types (sand, clay and intermediate) were identified as . .•i''-;;:";"•_ representatives of the range of common soils found hi Great Britain. • : Reference -. ; 1 ' /:-.:••';/,. was"; mide" to different volumes-of the 'Memoirs of the Soil Survey of Great - ': ; .'5:'

/•";• Britain1 (e.g; Avery 1964; . Ragg and Futty, 1967). The well described soil types : /. / . were collected.-from, locations in East Lothian described by Ragg and:Futty, (1967)." / / i.

, The sandy soil was collected from the alluvial deposits at Barley Mill (NT 458670) /;'• : . about 11. miles: East of ..Edinburgh and was predominantiy fine sand and silt with " • ':.:;•;,%;/ less than. 5%Jclay (<5;7on) (Alluvium). , : ' : , ; . • . . . • • , ' • . - • ' • • " ' . • " c-v '^-/ '•*.•; i-v^f,^"^//' ; • - ' • '-•-://•

.,.;.; The intermetiiate soil was collected from Merryhatton, 11 miles ENE of: Edinburgh.;-;,'.-" ///...;/;.;,. . -(NT: 471746);ahd consisted;of about 70% sand and silt with abouts25%: <^y (<5/t ^ f ' / : '-"y ./rni)(Winton Series, Win^tbn Association). : / .[ . ./;,• //.• ;.;^::.

.\Th'e;wci&yY»fl^^1:oqiiected from Cauldside, about 20 miles- NEsilt : andu,591794).;/anb^qv^ras/Vcbmposed/ of••., about;;' 40% .fine

:->m)((^uldside^Series^Stirling: Association). >; ; / : • : ? " ' ' ' . / ' • " / . : . •••••-•v;^-:^f&^^T/;-SS.S'^. .v?ij?-- !

;'t ! - llf|t ;|:gif p»^' " - < ' ' ' A +• . ^k*«/» -' 1 «««« +«^«*» . *'4t*^ A«h_K . M.K£T <_>_kd> * • Mv»^f •. j4««*r*««**«4^^4 #«««^4 . «»TK^»»»*' •'<• O4C*.'. \ffm ., f^f.-•'••. "~+. •', • •• •. 11 • • . '-•-•..top/ soil;.was removed and

... • v, „,'•.... „ '• . ; ' -V.X»..V , . . * - • • • •...-'......i;. ;•»,;; ; .^-• ••;. 7 ., ; ,-.\~',- \. .. ,>; -™ ..... -

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: -The asbestos minerals used had previously been supplied by the Central" Asbestos . '•'"••:'••';$•:'.".":•'•,• Company Ltd.;ir London, as typical: production grades ; of amosite,- crocidoiite^and' ; / ic/;/ chrysbtilei . A l l were: relatively coarse grades of fibres so approximateiy; 50g of -/ ' /:

each were /ground in/batches for about 15 seconds before being thoroughly mixed :: • -to "produce, a, fibre sample: with the consistency of soft asbestos lagging:.:. \ >:-/:,...^ / >;;;_.:;

'.'•'•' '/'/•"•'/:" ~X- -•i'^-'-'^3'V"?^:'iK4;/K;-..i-//;/-'/./>;;.;.,'' ;,• - • • • .--,,--:Vv-:'''^' • - ; ' v ' : : ''//--^•i^;i;^/v:'S/:/;|:vi/;:'"r^i£^" ::;:2.3V', ^Mibrinl.'a^yyaiiditkjn-of "Mixtures • .-;• ' . ' . ' / . ' • ! . • . . : : - ' " - ' .v ' " - .. /.';;'•' : ' 'v / ' ; ' " ' / / - r ' ' ; - ' r^' •''-v;^:

• - . All mixtures of asbestos and soil used in the tests'' were--prepaied;/at:_IO\L; v;:/^-lv''.-J;":' /^f:g;/;tf|?: v; | :

• / .Four- rnixnires/ bf.V.asbestos ;.T'and. ^loil.. were:;;..;pT«luced''':.;fbr';; each ^asbestos-soil : '••'-.:'•.;. /&;r^a.r;;,» |-combination with asbestos mass concentrations of. 1%, 0.1 %y 6.01% and; 01001 % < ; / ; / , 4 " ' " ::;:??

•'• making thirty-iBx mixtures hi .total..- ~ ;. •;:.': • ' . ' "':'."• •' • ' :" /"-/'> ''':-j ."-'~^~. '-.'•" ^^"/.^"T/'Ar-"'^:-'...'".• • ' 'v;> :---/:.5'. • • • • • ' ! . . '/-x..:. ••• - . ; . . . " • • • . . • • " . • • ' • . • • • - . '-.. • • . . : ' • ' , . . ' • ' . . , • • • ' • ' : . ; • ' l - - ' - '.>^/::i^:r/.-.^;;/--..-'.,:":.-/-;5:ii'>;i5 ';,?J:x

:;^t>.* ••>. • • .•.'••,--^.i%.:-;..-i...^- ••••• • • • • • . • • ; ' " . • ; . • : • : . . • . . ' • . . . ' • . : • ' • • 'y •-.-.:... - - . : . - .•'•...,;•'-.'-'/,.-;-'.-i .' . iT~' . i . ; . -,_:••. ^5*.,-j,:fV^^gT

Two different: procedures were used fax producing the four asbestos concentrations: in;.

L, "r

"•-.•••/ - : •••-•••. ' •:-•?. • ' - • . - - . . - - - ' . *•-• - ;-x?~"-.:Ky£~f4';s> '•' •' v^^^s^"-^ :• •':*£; i...••-.-;, : - . - r^ .---s ,v; . T^WV-,-^;e:/-- " ••-/U--r:,.;.3^:^-^.-.^^V.-'--^: .•«.•;:.• .;•:-;-/;.:. v., / <--<>?'-.ro"':;/"'. ' -,, ;->-^:V .%T;^V' V-^fj

for approximately 15 minutes." These were allowed to dry over '»everal days, ;•;.before final processing fusing a.- «k>w action food, processor. Five per. centmixtures were similarly produced. ;/ • "•' -./ .: . ; ' . .'. •" ;;v ;*'' ^; .'.

The 0.1 and 0.01% mixtures were prepared and mixed by diluting , aliqoots from /the 5% .mixtures with / t he reqiriredV; amount of soil. As with the other V",:preparations . blenders ':and food. processbrs were used: :..''• ":' • ; '--'<'" .^f'^

>•'."•*:""

Homogeneity, was checked by one- of the following two methods. In bothinstances, aqueous suspensions were prepared using weighed portions of .the mixturesand measured aliquots .were taken for filtration. / ;l For mixtures containingcfarysbtile, tew:? density -'depots-'••"'were:;'prepared on 018 Jon pore/size membrane.;filters from; five separate aliquots: for: optical fibre .counting - by phase 'contrast •optical microscopy (HSE, 1986 A). For ampbiboie mixtures, higher densitydeposits ("* 3.0 mg) were prepared on Nuclepore polycarbonate filters forassessment by X-ray diffraction (XRD). The integrated intensity of*the 001(10.5°20) diffraction peak was used as a measure of the asbestos content of themixture. The samples were considered to be homogeneous if XRD peak areas forequivalent soil loadings on filters differed by less than 10%. ,~

- ~ ^ V ~ ' ,4 t *•" V*,

Asbestos-soil mixtures of defined moisture content were prepared at GCT. ~ r Thesoils were dried at 50 °C until they were of stable weight then water was added to2 g sub-samples with moisture content defined as weight of., water/weight of Ibfl x1

100. i'2 g sub-samples of each asbestos/soil mixture were prepared with moisturecontent ranging from 0% to 50% with a total "number of 248 sub-samples. 7 •»*,

2.4 IOM Experimental Chambers and;Dnst Generation " "-

The experimental chambers used were the 1J3 m3 aluminium and Persper"boxes"*"*designed for animal dust mhalation experiments (Beckett, 1975). The chamberswere vented to atmosphere through a high efficiency filters. Negative pressure ~was maintained Jfl ihc chambeni to "prevent leakage, of fibres to the laboratory*danng dust generation. A flow of air of between 10 and 40 1 min"1 (depending ~" _on soil type) was passed into the chamber after miring with dust continuouslygenerated from a modified Timbrell dust dispenser (Beckett, 1975). *•

_ _The respuable dust 'concentrations were maintained at around 5 mg/m3~by settingthe flow at rates established by tests on the original soils. A period of --.thirtyminutes from the start of dust generation was allowed for the dust concentration tostabilise before sampling. ' •* ,

Each asbestos soil combination was tested in a sequence from the lowest to thehighest concentration - in order to minimise the. effects of cross contamination.After each test rim the chamber .:.;w : waslied/dowab.-irfth water and aBpwed to dryovernight with : clean air passing ; through the /cnamber. After the tests for ~each•oU/asbestos cbmbinatibn ;•••• (0:001% :to 1.0%)\ "were-rcompleted the input pipework wasalso renewed in a . further attempt to mfnim»r crbia^ contamination.r ...... ._., .v_.._.:< i . . . .

2JS GCT Experimental Chamber and Dust Generation '

An experimental chamber of 0.9 m3 , constnscttd of Perspex, w«s wed for an dust

'•,•.-• ••*>*•..

container situated at the centre of the . chamber.., ;: - Compressed/lif;-.was /-blown:through this chimney, via. a , solenoid: valve. . -By' means of an e^trbnic/.; tuner, -;thesolenoid valve 'could be opened for a •precise; .(* 10 m *) ! j'--?*^^ /l *i

: interval. The requirements; of the "dust: generation system^"'were::: torproduce/ a;uniform dust cloud throughout the central-; region of the chamber. The effects of

•air pressure, time of air blast.;and weight of soil charge were all investigated,,together with their inter-relationships. .It .was found that the most appropriatedust and fibre concentrations were obtained when a. 2; g charge was made airborneby. a 2 sec blast of air at 20 psi. -..v:-/• • - . - •„-.'. / •.•>!/, - '- • / //'./.!:-• •/'•.

Each asbestos/soil combkiation . was tested in sequence frpni lowest to highestasbestos "concentratibn. After each . test 'the .walls of 'this chamber.; were.; sprayed-with fine water sprays and wiped clean.:. --/They were then/sprayed .;wth: an:anti-static spray. . A n air extractor-fitted with high efficiency filters was/.then.attached to. the chamber and the latter evacuated for a minimum., of one hour.:After evacuation,- .airborne fibre concentrations" were "measured inside , the chamberand experimentation/"was ''only : resumed/when'' ;the airborne fibre concentratibn' was .found to be less-than r0.6l f/ml.7 " " "/': :/r';-""://"" • ' • ' :;;' '" ' ' ' " -7':'}.'':' '•;/'•' '•'

2.6. IOM Dust Sampling /

'.The respirable and 'total'; dust from each mixture was sampled using a MRE type1.13A gravimetric dust sampler / (bunmore «r al, 1964) and an IOM .vertical

. elutriator dust sampler, respectively/(Beckett 1975). ;. . /

The high dust concentrations permitted the evaluation of fibresoptical microscopy (OM); only, on low volume samples. A sequencevolume samples (6-8 samples of-8-20 litres) was:' therefore collectedmost of the "test period oh 0.8 fan pore size cellulose nitrate membranecowled open /head dust /samplers (HSE, 1986 A). Sampling

, rnls/minute land; It litre/minute were .used and the total samplingmost of ' uie-:du^uon./bf Jeaeh test (2j::'-.;;.;..3;r'hours but of; 4samples were conectedu^g; .me :same method with Nuclepore p^Iycarbb:(0.4 /on 'pore size) for/evaluation by Scanning Electron Microscopy (SEM)

Measurements were carried. out using uncontaminated soik with the SIMSLIN MarkH continuous dust monitor (Blackford and Harris, 1978) to> assess the consistency-''ofdust concentration during- individual experiments. Membrane filter samples werealso collected to provide a series of blank soil fibre concentrations. "

2.7 GCT Sampling /• . v .,,/.- ' . ' - ' " v " " ' / / / . ' ; ;• • , ;.;" ;. *;•;'•; ' . / / ' ' '•/.

Initial experiments recorded the variation in airborne fibre .concentration^ as afunction of time for samples of dry soil and wet soil. The; results," shown: inFigures 1 and 2, indicate a typical exponential type decay./ Although the/fibrelevels were significantly reduced by the addition of water,, the - feneral' timedependence of each. curve was "the same. The curves; were not substantiallydifferent for any of/the three: sbfl types. SampUng corjdrtibns were.-. standardisedat 20 minutes and started 30 minutes after the mitial generatibn of the clbnd. :.

As described above (2.6) the high dust concentrations restricted the sampfeFTT>rim«nts showed that volumes of 80 1 were suitable when using dry

:••••:&.-. .: ^$4"'•• '•.,:SI/'

:- 'iiSFM, *^.:?&:'-±i&

In all cases samples were collected on 0.8 /on cellulose nitrate membrane filters hicowled open.hg.ari dust samplers (MDHS 39,1988).

Respirable dust was sampled during the same test periods as above by drawing airat 1.9 I min"1 through 0.8 /on cellulose nitrate filters fitted in a CanrUa Cyclonesampling head.

2.8 IOM Repeat Tests

A proportion (about one quarter) of the tests were repeated to provide a qualitycontrol check on the results. Also, results were rejected if any of the gravimetricdust estimates were unreliable, e.g. when the respirable dust mass concentration wastoo tow (<3 mg/m3) or if the 'total* dust:respirable dusts ratios were" anomalous.Major contamination of chrysotile by needle-like fibre was observed in a fewsamples and the tests where these occurred were also repeated.

2.9 Analytical Methods

2.9.1 Airborne dust concentrations

In all tests (IOM, GCT) preweighed filters used for collection of respirable and'total* dust samples were re weighed, the mass of dust deposited determined' bydifference (HSE 1986 B) and airborne concentrations calculated from the volumesof air sampled.

. .The SIMSLJN dust sampling instrument was calibrated for individual sofl types bycomparing integrated dust counts with the results from the MRE type 113A samples(Bradley et al. 1983).

2.9.2 Airborne respirable fibre concentrations by opticalmicroscopy

In all tests the membrane filters were cleared with acetone vapour on microscopeSlides and mounted with triacetin according to MDHS 39 (HSE, 1986A). Fibreswere counted at IOM using Phase Contrast Optical Microscopy (PCOM) in twoways, the first according to the counting rules established in the EuropeanReference Method (ERMXHSE, 1986A) for asbestos fibre counting, and the secondaccording to the counting rules of the Central Reference Scheme (Crawford andThorpe, 1982). The main difference between the two sets of rules is that theformer ignores fibres which are touching non-respirabJe particles (> 3 fandiameter) while the latter includes such fibres in the count.

The fibre counts at GCT were produced by PCOM using a modification of theERM essentially the same as the CRS rules.

At each laboratory, two principal fibre counters were employed and a proportion ofthe filters -were recounted by a different counter to provide for quality controlcfaecis on the resuhs. AD ex counters participate satisfactorily in RICE quafityassurance scheme for fibre counting (Crawford et al, 1984).

.'.Forltfce 1OM/tMtt/t/~c& . .. . . . . . . . .t^.-A:' coikintraUon^throuihbm:; the- period:, of /each/, test//. For, each ; individual, test, the•^t^ntial-«mpl*f-: (Secdon/;2.6)/were;.: u^"fibre" cbncentradoni .from; uSe 'sums!br..the;fibres found,, diettmpiedtnd the p'roportlbri/of:.die/nher ireis

2,9.3 Statistical tntlytli of data

Fibre couhti'^ite^to^'detSifle^/I^rborae ' fibre./(johcentratioruji^Poliaon variables

U used to "determine . tirborne fibre.- concentrations;;;ire -;distributed.\tiiableslu^e3tlng:ithat^ai/log-linesr .model could; be^ approprUtely: fitted ;to.

au^^^f^:^^f^y^ •f'-:'^!^ii:'jy^^^A^K-^^:'-..; •'•! .-'•'"•"]•.•": ;',./:•. ' •. i ;O..; :'v;V'-'"\ :-. '_' ' • - . ' ' • ' ' " . • - ' '" .« ' " ' : « ' - - • -"'j. "«'.-«'-• -i :_:••-**1"1.--!'.. J«. ••!

.jpiJ i y ;

^-^t!M:'>-"JV"-:' ','.:>,•'!'. • ' • •

^//l/-/:

: A terierailied / linear-: model , was /formulated for,. the^relationship,: tet^n?:;die^logarithm •. of die observed tirborne i fibre:concehtration arid•; ficton^fo^«»bestM2*^P?»r

" ibil type,..tibestca/content, of, die ibil arid for' interactions of • 'diese/ftctoriTwh'lch?.was, expreaed/ M/',,/;^;/.;;^//'/// . - ' • „ - • •> ' , . •• ' //:'/. / • ; • • • - ; •''• • --'-:'^ '" ^-; i:-\-/^: v-^

•log'f|jk *. &'+;t{^-ij:+?c^+::(*ty'(K)fr +i'(«)jlc'.t/«4jk". ' '\,*?\: • • '

• ' ' V%i''%'^~M;.r:tV^ ^ . - V - • ' . . <,;-,,.. - . . • • ; ; . - . , . - . . - .

. : f «• airborne fibreocbhcentradbn ;; v/ - ./'•---'.-" : . . " - • ' • " . • ' • • - ' . • • •:'-//.':•/:"X?^i-'/;—:,m », airborne1 fibre cbricen^atJon;. from 0.001% amosite in clay //"/>S:;:;/:v;;

' •'-- ."• -. *• "^^ 'i^^^^rf^^ ' yp6' V::-'.-"^/ S~'^}"$''.-:'~^v'^£.'' .;//-^;-!-;:£rS^v^V^• '- . r «J^riibieVrtcto1r|fersoiirt^:^^ •"•:/;/ - . ; '-'// •*'• ^'"•''•^:^&$Jy?-\

': .c »;variaible factor* fbr, asbestos content of soil / '.-'-.^ --:/,/;, •'//^S-?.^-^-'' ^/•4s,:'•ic,/.ci;:>^•mterac;dve/:f^brs/h^voiving a;-c and ; «- ^;':;;'v:V i,y:,'^^t.^Vy^.^'^

;• ' '' ejjjc""-/any .residual' tystemadc1 errors"'.":-'-,- ;. •- ' ' '"""/';./. • -'/i,,-'':;/;:/^:;;;-:///-\'':'-;^H;:x;

Regression analysis of the model fitted to the data and analysis -of/deviance: was '•.. / ;/ycarried out using die GENSTAT computer program (ALYEY & at-, 1983) !; / ; g /v^.;..:

•;•.'••' ' . ; • • • ' : ' . •:^///'- //•/^."•^/wi/'f-.r/--; " ' • ; •:!:.''/'•''.;•:'' 'V-' ,:•--T-/':"-;'^''./-'1-/-K^-v'-^v(^:^i;j^/;5^-'.;

2.9.4 Airborne: Asbestos arid other Fibre Concentrations by Scanning ' . " . : ; :Electron Microscopy (IOM) ^ //; , : /-/ /

The polycarbonate filters were cut, mounted on standard 13 mm diameter sample/• " ' : :holders and coated widi gold prior to examinadon by SEM.''.^;;;;_The':'/filters;,;were''searched at 5000X magnification and ail respirable fibres (>5 /mi tong,: <3V/un 1diameter, aspect ratio >3:1) were measured, counted, analysed ...by/iewe^..-.diip«^w:''/:''!; ;/;:/''••.X-ray spectroscopy and .identified. Six hundred fields of view: were searched/or/;- -50 respirable fibres'-were analysed, whichever came first. -../

'-.•'':->S^-.'-

/ results from die/individual dust generation . tests are", shown in Table S.l.'-^•.v//;:;These.: are. die respirable and 'total' .dust /concentrations, .^die: airborne, fibre'•:.• /''/•' concentrations for fibres counted by conventional ,,'ERM rules and: for ::tiiose'fibres/!";//counted /using! die7 CRS rules (Section/:2.7.2);;and1/tiie • normalised .airborne .;.fibre•/>•'-'//concentrations, obtained by. "dividingfthe fibre .concentrations by, die ntspifable dust

:; ..;-;;^:"<Mncenrratibns.:;(f,;;r^^ /.;/f/:;(^ ''/--V^"' v^.r. .;.-•

; The fibre concentrations produced by the CRS rules were higher tiian die ERM"; - concentrations, and / die ratios "between die two differed considerably. • .The samples• . were heavily contaminated with non-fibrous particulates. The modified CRS rules:"/.-•/are. <x>risidered;;:to:^ permit die counting of

://:' n fibres -which,"-touch-, or appear": to/touch Articles:'"/:/This/avoids subjective decisions, ;..r concerning/ Hie^^; exclusion^ of such fibres from counts using ERM rules.

////Table 3:2 shows: die'^^ and *« average'/ / 'normalised "fibre/concentiations for die • tests grouped by asbesios type, by soil type;.,;:/.' a n d a s overall - average.... ;/.-.• v.-;.;...;".': A./ ' . • • • • ' • ' . • • ' . ' ' . ' < : • • ' - • ' f c

. 3 . 2 Dust Concentrations '/../'

: Table 3.3 "gives. die averages "of the dust concentrations achieved for each of die/'•soil types in.the;tests. ;/. '.:•!••(,• ' . • . • . ' • • - : . ' . . •"'•. ,

-The average concentration of respuable dust achieved in die chambers was 5.53 mg• m~3 (SD 1.61) which was close to die target concentration of 5 mg m~3. There

was some variation between die individual soils, witii die average clay dustconcentratibn^ the highest at 6.9 mg m~3; compared to 5.1 mg m~3 for the sand

; arid. 4.6 mg: m~3. for die:•:'Intermediate/'soil.' ; ;

The average 'total* dust concehteation was 7.3 mg m~3 (SD 2.37) with the average'/.for die clay soil of 9.4 mg m~3 compared: to .6.9 mg m~3 for the sand and 5.7

mg m~3;-for die ;hitermediate soil... ":. //

The. ratios /.between -/die -respirable and 'total* dust concentration were /very similarfor die different soils at 0.74 for die clay, 0.81 for die intermediate soil and 0.75for" die sand; the combined average was' 0.77 (SD 0.09). .

. . . . . . , .Calibration of the -/STVreT TN •'•WM .-- carried otrt by comparing the average voltage

.reading, obtained by: direct reading" . from the. integrator, .of the SIMSLIN" andcalculated i from die printed record, with : die mass ^ concentration obtained from dieMRE = gravimetric dust sampler. ; These alkiwed ti» SIMSLES/ voltage readout to beconverted., directly to respirable dust concentrations- in/otiier tests. The clay had acalibration of 0.66 mg m~3/volt, die mtermediate soil 0.94 mg m~'/voh and thesand 1J2 mg m~3/voit on the reading of the SIMSLIN.

• -.- --i*

0^1• >/£:<••

3.3

10

Airborne Respirabie Fibre Concentrations by Optical.^Microscopy . • /•"' - : • • : ' . . . - . - • '

The average respirable fibre concentrations by PCOM for all soil: and all asbestostypes were 'highest for die 1% mixtures at 10.8 f ml"1 and were progressivelytower for. each of die lower - concentration mixtures in turn,, widi 0.11 f^ml""1

found for 'the 0.001% mixtures. './•/ / / , l .',,?:• v : .:' ' -.' '.*•:•'•.

While the tenfold reduction in asbestos content of die mixtures from 1.0% to 0.1%produced almost a tenfold .reduction in "airborne fibre concentration, subsequentreductions by factors of ten. in die asbestos'content brought only reductions in fibreconcentration by factors of about 3 and 4. (Table 3.2).

This general picture for all mixtures was repeated in average figures for eachasbestos type and for each soil type as shown/in Table 3.2. JThe differencesbetween die f asbestos types are clear, with chrysotile consistently producing vtiielowest fibre concentration hi each test, and crocidolite the highest concentrations; •

Similarly,, in all but die 0.001 % asbestos mixtures the fibre concentrations variedsystematically widi soil types. /: The fibre concentrations generated from die claymixtures were the lowest and mbse from the sand soil mixtures were me highest.

Of die airborne fibre concentrations found in die individual tests (Table 3.1) diehighest were those from the 1% crocidolite-sand mixture (average 21.6' f ml"1)while the lowest concentration for die 1% mixtures were, those from the chrysotilemixtures widi the clay and intermediate soils (average 5.8 f ml"1). " " '.

Within the 1% and 0.1% mixtures die higher fibre concentrations were found wididie amosite and crocidolite, sand and intermediate combinations while thecombinations including chrysotile or clay were usually lower. .Similar/patternswere also found widi. the lower asbestos content mixtures although the trend*' wasless clear. .'/."./.!' ' : .<, . ' • / • " . -

A summary of die analysis of deviance in the log-luiear statistical model is shownin Table 3.4. ,

The reduction hi deviance introduced by die progressive inclusion of * die;variousfactors (asbestos content and type, and soil type,!. 2.9.3) into the model.::and i die.mean deviance, ratios can/be used as a test of the significance .of each factor;These show/diat the / asbestos content of the soil is a/ very significant/factorcontrolling airborne fibre concentrations and, that the effects of soil type or asbestos-type, although minor in comparison, are still significant. Similar analysis carriedout including factors for interaction between these primary influences showed nosignificant improvement in fit between die model and the data.

Table 3.5 enumerates (as exponentials or as multipliers) the factors used, in thetog-linear model (as in 2.9.3) for each combination of asbestos type, soil type andasbestos content, and could be used to produce an 'estimate: of fibre:- concentration.For example, die expected airborne/fibre- concentration/ (in. a 5: taf m~3."_dust: -cloud) from the crocidolite/sand combination it': the 1%/asbestos content, level is- -/

exp (-2.534 + 0.128 + O.S37 + 4_56S) = 20 f mi"

" , . 3 . 4 ' A i r b o r n e Respirable Fibre Concentrations Normalised for.;.':.' - Respirable Dust Concentrations

/ - ; The airborne .fibre concentrations assessed using die CRS method (modified-ERM);.."• ";. were normalised ..to 1 mg m~3. respirable dust concentration to reduce: the- influence. .-•/

• of experimental difference between die tests. ; ' " ;?f

./ Because the dust concentrations were .fairly consistent during, die tests die patterns. already indicatedfor the airborne fibre concentrations repeated with the normalised

' • ' ' ; • concentrations"., • ; . ' ' . • ,. //,/• ' . . ' . - ' ' • • /'// .//"' . ' • ' •

••:\ ; 7 The . normalised concentrations/were highest for die 1% content asbestos mixtures;/. - • and: reduced progressively along, with the asbestos content (Table 3.2, Figure 3). /

/;.-:. The reductions m the normalised concentrations were, not: generally proportionate - to •' the reductions in asbestos content; • drily; diat'between the 1% and 0.1%/produced,

a decrease in normalised concentration by a factor of ten. :, '••-.The overall/;.thousand-fold - reduction • from ; 1% ;:to 0.001%.. in asbestos content 'produced only a :

•/./.one hundred-fold reduction in the concentrations. ""'/.•".-' " -V *• ' . - ; ' ' " - : - ." /" : ; / ' / ' /

./ There; were clear differences between die average normalised concentrations for dieasbestos types.(Table 3.2, Figure 4), widi the crocidolite consistendy producing thehighest normalised concentration and chrysbtile die lowest. . . . . ; . / , ^

The average .normalised fibre concentrations for the sandy soil were generally the/ / highest except for /the 6.001 %' mixtures, and the clay soil ratios were always the//,•'•";:lowest;'-.;"'-.''""";" '///'/•:''"' ' ' • . ' ' ' . . ; . . . ' • ' . ' • ' . /" ' ' . . / • - ' -./'-.//-;-v:;/^^v-'-

The highest . normalised concentration for any of the tests was found with the .;. / crocidolite/sand 1%= mixture (3.78). The mixtures containing sand, ;crocidolite or^

;.-;amosite gave generally higher concentrations tiian the clay and chrysotfle^mixtures. :;/ : ;j . The lowe^ concentration among the 1% mixtures ..was found widi ..the: ;;',"' //clay/crocidpUte-. combination ,.(0.83) aldiough die chrysotile relay. concentration j.(0:84), ;;

-••:-: /v:--v". .Svv/v;.;/'/ '"^•/;;:•//,••;!,//.T:'';/\ '.:-./.-•/ - • : • ' ; ./"/•" '•-'',--; -"..-/• '!:.-- ' ':;/'"^:vrThe normalised airborne fibre concentrations for die mdividual mixtures are showngrouped by fibre types in -Figures 6a, b and c and grouped by;.'soil';,.types:;.in, ..,::...':':/"v

:.c.1v';/.,>;//''/Figures 7a,:;b: and c. : /.The coricentrations from the sand mixtures are: ^higher^than-.v^^diose for ;the clay; mbrtures: for all asbestos types (Figure 6). /The norrnalise^//;/

"concentrations for intermediate "soil are similar to die concentrations/from/clay ;

mixtures for chrysotile, similar to those from die sand mixtures for crocidolite andin'between for/the amosite mixtures. . . . • , . . . - - . • • ' . ' ".. / ' ' . : ; . . ." ^-//v/r^/-/'^^-;/?

This point'is further brought out in Figure 7, where the lines'for nonnalised .fibre "concentra'tions for the three asbestos varieties hi the clays are close together, andlow (Figure 7a), and those for the mixtures in the sands: close together, and high"(Figure 7c) wniie the lines are widely spread for the hitermediate soils (Figure 7b).In odier words the influence, of fibre type on die normalised fibre concentrations "is . ... .,. ; ,,.,.,.greatest, with die intermediate soil. • ' - ; . - '•/• ... ' "' . . ' ; , •':•""••::• :".. /-'.v^V

3>5 . : Hbre Concentrations associated with Uncbntaminated Soils , : " - .-: - .-.\--J

The airborne respirable fibre concentrations found using the CRS rules for samplesirrino" MiriV elite -nj*r+ all Vror with th« Sand

. . . . . . .0.005 f ml~''7mg m~3, and'the clay. 0.01 rml~1/mg m73.

•/"-.'v^-higherTd^/ .:/; 15-30 minutes; after starting; the dust generator,; ^Ti^^Kwe^E^^^iS^^^a^^ly^ ' ' ' "'•'

." ::i */*'*• •m-*?**-*'**** ^. rgflsonflfoly-. consistent conccntrst^on~--$s *tITI• "'^ffjc^v ssudy;

./ io.;:

":/" cbntelit^iis' Opl^) -'w^rgieate?/d^^ ; i'; "-i--1::;?:'' :-; ; counts/fbr'.'die./fbrnier would, be- subjectJ' to/;a'; gf^ter.^rangecpf-^stetistic^i-.vsinatibn-' ' .'•". ..-"•-. - j. : t .."-•--•?-;"-^^- "'bw^^fibre/^^ .,;/-"./'S^-i

>'•• tf%^M^.AM+^-+C^U^ w«r.«iT^ ^-vrilottv ffi*» - wt/1*»r-•-trai-Tti-fTrin • ITI / t ii* •• TV*<iiTf?nfr v '7 '• •> : . . - - : •/'

«e. proportion; of no

:":• rneasure^;/by ;SEM::;Wcre/"g^er^; : :-5:/r\;/' /BCX3M/cbnoraba^

'A/summary-'cf/.die repeated tests is given in Tabie 3.7. Repeat runs were largelycarried out /using die mixtures wrth low asbestos contents/: (0.01 and:: 0.001%)

^~y%m~-

by factors of-about 4

n-*M!

,•;'• •••*?.: •£•?•••'-& A&fZi.

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^-^•'•..^'v^^^rS::-'"' ' ;-"':*- '-'- A«^^5f V-".V^3«&*!•»

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.".'.'•:. '-':r/?/r/%i:!i;5^

. /y-^W^Il. .. •>--'^-.,:-'-:%ig"

-,:,^:'; ' |: .-.-, ! ': • • • • : • ..-K**

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|!»3$$£S^^^:^,^-:^^^^^''^:K' ^fii1."1' '.. •&.-'/ /•"^.^•=:rSS-;/*/;' :

' r *v. jT ,, .-.••»> • - .

t'i"''*Vv'"'"*'.V.r*' "•••" \. »'•*-"",•St-^V;"":;1-^r?2™:"-'^;J..s"':.,i.-'-.:.V,T~V. ~ • /• ' ;• .'.-. (:

T.'f.;.''-''.fl':'" -• '••"" ' .•• ''"*'' >"'

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gf/'/The^ rejpirabJe. dust/cohcen'tfatlohs. achieved1:'with /the : dry soils; shown/In Table/3.3a^"/./:were • much'-Jower fthan^iho«e-.;bbtaine<f;iri;'the/IOM chamber "expfiriments/'/v" ;;/

; • ' The" airborne- fibre- concentrations' for dry asbestos/soli;mixtures:'horrnaJIsed-'toi'l/;nigj./--^/^j::^;^;. m ~ ' _ rezplrable dust, are/shown In Table:4.1. . ' They^'.range 'fro^:^l3/J'-{&ml~^:mgl?r^^^-'

': ".m~*;. for;,l%/araoslte• Ih/sahd':rto! 6.01 fy ml~ ' : mg m~*':(or .sonier of • d^:'0^boi%./5'\&V^^::;r^::vrflI»tures',/'^'fQ«'|p;^;i^ '-/"/^ -- ' '"*. '••.• -. w^^•:^•>^'i-?•''•sviKi^^^•<i*'•! ".'X^4?-

'..r ,The average respirable- fibre concsntratJons generated by ail soils arid ail'.'asbestos//:.;^/•:..?-^t-^/'types were highest for trie '1% mixture and were progressively lower for each Ib^r' ' wconcentration mixture. . . ' ' / ' - " ' - ' ' ' ' " ' . " • " ' • • * ' • • - • • '.:.•'"'•-

£:,'-:TaWe;..'4v2;r'shbwi.f'::;the.;.;pyerall, average normalised fihre; concentrations - 'grouped^fyffi$^£ii-&*:?.••••: asbestos tvbe: and bV sbli';' tvoe..'-" -••> '-^: //:/' '•' • -.-".•.-.•:.;//-,':"/. \''^:ffir^^s^^;^^M^f^^^'.

;;:;-:vf.Genmliy/;^heJte^fbJd./red^:*;-;.: "•• 0.1 % Ipybduc^/cbrricspb/ridlhgiy ^L . /* CItK*•>>••*AH*A.-""mi^iA»'***'*r**-m+' •': W«. ' f—. ^d AU. "

.4.2 . Effects of Soil Wetness

'Table ;4;3 shows die results"/of die 248 (36 asbestos/soil. combinations/;janc

cohcehtratioh' onconcentration decreased

. The. /results suggest 'that./ the"'.; /'fatrdduction' of the first, greatestl/effectv particularly^: in j^e^case/of arnosite/ and/ water. were •'. less" effective although . still necessary to -achieve:tnebelowi-arger asbestos concentrations in' soil required" more- water to; achieve dus". ,-.:'.(5p%'for l%.'amcsite in sand).:": • /• . •''''. "• ~' '/ / . . . / " "" ; :" '-"-'" ." /"/ ' /

. - *• ".-:•'• •-• -. ; • — • . , „ • _.T» •• . i - ' •»•• • *•• —. • ' • . • "'*"'— -• — • • • *- - « * - - . .-pv -* , „£,. -.-• '• _ .^ -; ~fi

For a /given ^co^r|cwatration' sandy ^soils r

require more water^/Jtfian^ other/rvpes; t«Jt no clear pattern has emerged and furthervrork , would, be/reaped ; to-'^ ; . "'v"::.''!--•<.*•?>•; ''• ' .'

' '' " * . - • •....•." .','-.-•• . . . . .; - „ • • . • . . , - , - • • ' . - "..'* - ".. *^** . . . . _ • '•' - • '" "'- , ' - . • • ; t •'•''•' • . . * - • • - . ' • ' -'.':. " . . . • . • ' . " .

- : - ' / " -- : / ' 5. 'DISCUSSION '

Airborne Fibre Concentrations '/from Dry Soils

of die data shows that die

respirabl? dusVconcentradon to the nuisance dust occupational exposure limit (OEL)of 5 mg m-3 (HSE, 1987). \ • ^ / \

There was'coed agreement' between the results from both sets olsoils../ The similarity-of the results for; given dust concentrations aicontents suggests that: the dust geheration techniques were of secondary,,

.in establishing die relationship; between dust and fibre concentrations.

S-he"';fibre'con^ m^-K" - ••;*!?•

me nore conccnirauora mca*u»tu- «» YT—.-,- :" , r ^j,J;i,» t«' TinifM-in : - " - f ^ •those; reported Davis, CIWSfcfeKiOQ* ,asbestos dust clouds/Pf^^v^^^^igt^^Dust Generator where^between 275^i-S75.,t^-:Tar\,v^.t^^^^«M^ ^ ,. :LJU3L \_>ciiCiauja wnwiw . i**.»"*.~« " • " . - . " — . . . . . , - . . . . • - - ; _ _ - • • - . . • • • ' / » r\r —1. "•!-. — -'-'l-."i";' ICt.-- A* :'.-.-,[^ V..-.-'.-A-.-" iU.i-^i-s:-mass concentration of .5: mg m'3: (i.e; 2.75: ^•^^•^^^^^^^^^^^^S, mg : m-3).- / There- was >a progressive/ reduction in ™/^C^g|^=W "^^i^^at a given .lust concentration with Cueing amounts. of asbestc*Jn,the^^this Eduction 'was:,not proportionate, to,the/ reduction_.ta, "^-^^% ,' ^fiPS»0.1%«VVidi--0.1%V?ancL..ofteri;o:ol%,,of.«^. ,^,-:v^-'-i-2.-_,»i-;:rj-^^'n^ 'f^i-r: Control-Limit-, for. crc*idcUte.y and: amcsite >;^.^j£i#i$&£

• - • - • - • ' ations>.fi^ib^w;.;5;-:-^t|i^i*^^»t--«Wi''^«ir«iTu-«'7l{mit " 'ruftrt- 'sJ:":^;:^

There are problems of fibre counting with .these low asbestos Tfonc£^0^*^make correct assessment of the: potential hazards very <^£V- ^^SIOM tests,: samples^ 'between 8: and 24 litres of . . ^^Sl ^^Presence/of large amounts^ other/mineral dust. •:\p:^£^.<%ZSS%*£S&calcukted from cwaulative counts over 6-8 samples collected seqieach test. .The cumulative counts/would then provide reasonable;the.fibre concentrations down to"about 0.01 fibres per ml. ; : - ' .the- .gbbd/:agree™nt/.;tetween;vthe '.'two. sets; ol,.;tests and^

-•repeatabulty.;.of;die/itxpelrimeh^ .:.'•:.'/v-/;'/ //.v;-///-

The airborne '"fibre" concentrations, associated with, thethan:tbose associated with '0.001%: amosite in. clay. These

18

-sr\ «S^ws--;::'x;'isiS,S5^-:-':/i«fS---://:?::S«Sp

.' • ''•" •••".,"..'' • .'-"' - • ' ~"-.-'.'la .. '• T: " :.'p*j§SiS5

The electron microscope examinations carried out/oh the K>M tests confirmed" thatasbestos fibres were present in the dust clouds, produced fron die low concentrationmixtures and diat there were few asbestiform minerals _in die Wank ioik. ;/;Tbe,.non-asbestcs fibres" which accounted, for' substantial proportions of die.;htspirabie;fibres found by EM hi samples 'collected from mixtures, with low asbestos coctentconsisted largely of elongated clay;; pardcles or/chains of particles. It/is/likely that:many;., of "/'these would not ha've been counted^ as fibres by./phase, contrast opticalmicroscopy;/ not becausei they were discriminated against during counting but radierbecause diey would not have been perceived as fibres at all (Plate 1).

5.2 The Effects of Different Soil and Asbestos Types /

The effects of fibre type arid soil type on me airborne fibre concentrations are/minor in comparison to the bulk asbestos content. However, die natures of thefibre and of/the soil do have a real effect. . For a given'asbestos concentration^fcfsoil it is predicted from die model diat die airbbrnerfibre c^ncenG^tions coulddiffer .by factors of around 5 accprdmgfto die asbcitosY.^

;.rn;

could be due. to; various factors. : : It may/be/tiiat die"proportionin the . clay mixture. was higher, and, therefore^ tc»/achieve;; aidust ck " " " " - - - - - - - - - - - - - - ••""••-- • •— -*-••

airborneAlternatively

'binding oh to die fibres. .-. This, could"dtherj"'pfe'ventv$^. ... ** , . * ' . , . - - . ' - . • » . . . . . • - ' - • - • • • • - . ; . - - . . " . • • m •'• •- '•'-+»'-'*. ••'••••* •••" ••'£$?' >.'Vi>"^*« - '••' ••',' -\i*,!Sp|mw "rfi.'".". ' " •;•- ' - • • ' r^ii/,«v/£V;.-'i»!&«»i«A.**.'-V —. *"••''*;(•." ;:'*•

Both . diese': factors appear to: be /important...;ith^R.^eiay,-:: m'ncraisV'"'

respirablei;"\p\,total /dust'/MncenCratibns. fromthat. die^'effect/ is most^'rnarked/:with " .chrysbtile -/which;-'is-^the^fibie--".;typ^::iiK^;susceptable/to entanglement (Plate 2). // The/effect/.isj alsoi qun^;:/marked^'tor,:rdxtures of/chrysodle/m/mtermother /harid7~' it fa:""difficultJ'.id explain '.die variations:"',in/concentrations from the amosite;. mixtures; in terms of binding effects iasyvoosate''''&much less susceptible to entanglement-of diis type (Plate 3) because of its surface jshape and other physical prbperties (Hodgson; 1965).: ;/ / / '".;:"/"

There rare,, consistent effects on the hormalisied' _ak6brne'v.';/re3p^ta_*^,;/-.fibiie._concentrations .from different fibre types in a given spii. ; .Crocidolite/ almostmyariably;;:prbduces: higher normalised fibre /concentrations;; _'fen|do«^cBryiot^^wJhUe;'die position/or amosite varies with, soil ^pei;.;-/''/:;T^:;n»y-/i'efl(ea- ^a^'inKH^t'abiiity/for crpciAJIite .to - generate mbre airborne r fibre3';?per^-;unitS''Ji[«BTolrj^/may/;be:3faVdifference;hi die suppressent effects of clay particles, binding;; toi "die three different:asbestos types as mentioned earlier. Given die established differences in thesurface properties of^chrysotile and die amphibote minerals.1965) and. the tendency for/chrysbtile__;,to/: prbdix» more and./finer;"/fibres:

amc«he: at/.least it is suggested.""diat -the" duTereaces hi die normalised fibreconcentrations for the three asbestos types are largely the result of die differingsucnressant effect of the clav. minerals. • -•" ' : " ''•

.»--- - i . i i-••.••!• .'-. V*' r-?.'.-'-. A^i-.':>. '-i..'-*iI;v-'> 'vr^-:-r:.' .-•• fv'- i ' : i?*'.-:**-:. S^-'^Vr'-'.*1--.r-:.^- -'wf-

. : " ' '') ••-• '<?V • ' • •'/.: /%,l;K V-? .tfe;^

'; ;:^~'<x/M:'; MlC'r/iiii./• '•' -o./'V:'•"•--.rV.W..-.- r ''-...•... .'.r-,"iC?,-?-"jTv '.'

5;3; "•. .Dust Generation • ' - , ' ' • : : / . . . . . //

The choice of dust generation rnedibd could influence the results^V -.No single, : ,.•/;.£%••generation method could be considered /as representadve of dw . wjd^ranje^ work.,.,.-. - . ;,;.

••'practices which 'may 'produce dust on i cbntaminatea site. , ^^^methcd^of,,durt;.. .-;s. . ..: ;^/generation,used':it IOM (Modified Timbrell Dust 'Geiierafor)(TIX3):,w.«cogmsed;; .- .... • '/ f.

' as mbderatelyviggressive in comparison to'^ia^^iaei^ds^^^^ia^^^bKmx^^^ . . , . • ;--..of ' its lower tendency to blockage, by grit /particles' and because of-';^:neceaity, to^_ - , vgenerate" dust at relatively constant concentradbhs over a four nour period.,.:;& It . ,,,-operates by advancing a plug, of the loosely packed material down- a ; hollow tobe. - :intoi-'avsmali cylindrical chamber inside which a.rotating, vane scrapes dust;.from. the,. ;^.--,; / • - : >

'front of the/plug.' A compressed air.feed.,:tt«i7Hte'r_the:^^: the chamber, .i/:, This: beating,, action /of/the vanes may . release fibres.-;tomv.binding^:^-i^^:^particles';%ore/^ffecdvely;/'than;r;other-.; dust generation /methods ^'dius^facre^mg^^^^;;.^-./'airborne fibre "coricentrations.""- '"•'//'. '.. ':/•. // . . - , . - • '•••• V'^-W'^'-^.^^^^.Mi^-^i^Jo^'/- "'^vY.",- ///f V../.-.V/:/•; K:-:^,:-- -'•...-, v/,//;:.,••• • ,v-' :^r;^.^r^^^.-^S«^%^;^^:--: 'The rnain difficulty arising/from die use"of/the TDG appeared to. occur^enxthe.;i; :^;^.face^bf./th'eVadvancing'soil plug collapsed (because"of its lack of physical..strength):.r.:;g;;.£.-:v;v>,

:leading to:;an increase in dust and fibre concentration within/the dua^.fpUa^^^^^::.^by'^gradual; redui;don/as/;shbw^"arise- at^anf/pohlt 'hi die dust generation and could; not ;Tbe/.^y^id^ -«#imiit:artifically binding/die soils: ;/ In spite of; these d\r-—^--- ••"••«-.*«'concentrations/measured over the four hour periods wereconcentration/ of; 5/mg ~m~*/for respirable, dust

The 'fact diat.-die 'dust •''concentrations.'.';could 'increase by

. ^• indiyidual: sarhple/ fibre; cbnceritrations were/ observed''coritent.;m^ures:;'"':;'''.These. were, primarily/associated

- associated widi'/counting 'low density samples ; (Crawford/cbntinubus/: sampling: for/gravimetric-: dust; concentrations

' tiiefusevof/ time;; we5ghtedr;averages/reduce; :'the;;c effects'/ of/such variations, /"providmg more reliable:normalised fibre concentrations. This is borne out by die repeatdifferences between test runs were generally sniall

The transient dust cloud generation, methodi: used at GCT;to" diat used:: at IOM, and die" sampling /strategy, involvingdust generation to allow die dust to setde, .was. verynbrmalised; f i b r e ' / < » r i e ^ t r a u o T O - : f r o m "'the--two/tests. s_ . . . .majr 'be ""'• a:? general relationship / between ;.. respirable dust p:: and"concentrations. It is ".therefore/ possible that die ^normalisedconcentration is independent of die type of dust generation me*110*1

further research would be required to confirm' this.

5:4 : i: Effects of dw Addition of Water to the AsbestosASofl

''The- 'results, from the';' GCT /study s h o w ' .''• generated' from /contaminated' soils are- fready/'reduced, -bydxi soil. : The imcunt of water required to'reduce feveis; .'tb-'-rdepesds. primarily on. d» amount of ccmtamination of the\.sofl'-/and

Starting widi/;initial fibre concentrations of/ more dian 5 f ml~]^fromvdry-soil,/!fibre concentrations, can be reduced to less dian the clearance vihdkatbr of 6.01: ^ ^ml" '..by .the addition of between'' 20 and 50% water. ' . _ .' ,;/;/ '/i.,; :,-^^': '.^H"'^^

f /die first: 5/.or""1iO%/ water had. a -greater,, effect ;{t!uin;'«bi ^dlfftrencta/.; observed t in;/the 1 progressiye -:' addid<ms' Jwould require/i/?3^5:;/: / |3;>

-:rfuriier/sr^ejan^,/to/expiaia:^ ' ~~*'' •--^•°"-/"large"

practical/

-The..

The workrwith/die dryasbestos/soil mixtures /has shown :/tiiat«ti-.. - -^i-^'^j^ij.^-J-;---!-i!j- ---i-'--«^"•«•*.', -:V.-j-^"--.iV. : : Jl-_,ii,--: j -•_.

1. ,; .; Even small/proportionsairborne respirable asbestos

37 ;--'':;v;-/...Mixturw'can produce airborne : respirable "asbestos "

." dust clouds where the: "respirable dust : concentrations" " - • " * ' ' '•

Airborne.; fibre concentrations are reduced

, To decrease levelsprincipally "on ; e-: tevel •

ml"1 by die application of some 50% water to die soil.

ACKNOWLEDGEMENTS

Thanks are due to die numerous technical and clerical staff at Glasgow College of//; / / ;Technology and die Institute of Occupational Medicine. for dieir practical assistancein. the course of die study. . / : „ ,. - • • • • • • - . . . *~ ^i

•=i '"f"^"v"'V*^: , ': • '. ..<- . :

.. ,. . . . . . . . - . . - .

' ' • s ' : ' ' ' ' - ; : : ' ' - • - " ' ; :

- i - . ' : ; „ • . < • •,. - • v-.y > -v>*f- ••»«5a..i< v.v.v^*«* •!'«--•

. .v -?^-.• : . . - . 4 ^ - . : . • .-••.-. ••i-:nv. ..jCir,;:S**K.-ri .>',.-.«.;».S?i.':-..*v; .•.•:••',•••%,

'. '•' •• .:'-':'!":'. -' -..:';;-.:,V. :'^.,:^ f^'^-^A-^'''^^-^"^^;':^^^^;""-'•' ' "- . : . ' ' : - . . • - . - : • . — ' • • . .' V:.-'.-- -"-.-.' >:^i:'.-..v-*v.--^j3;;-.<£c *;"-:.'-- i'

' • "-^.'.„.".'•'"-: .'•^•••''-: '•' "p.-.t--.-^^-.;::-.',.;VT'i;.v.sr^r>V">!S?wir\^

••• r; /:'-••: !'' r;-^?-:':-;::::-::S"/-s;;'#teiS

> • - ' • • . '• ' ' .-REFERENCES' . . ;:

' '••' ' :;/'" / : ' " , ; : ' v ' ' ' : ' 'V-•>.'/•://'•:•/•//;'/•-.>/ / ' / - . . ' : . . . / • " ' - ' . - , ; • • * :../:•'/"^-'v^-VA/-r /^C'NV^ADDISON J, JONES AD.. (In preparation) Evaluation of potential hazard /from //:.;••;/"/>,:asbestos /as a minor.'component of. vermiculite. :/ .././:/%./';;•• ^.v'^/v///-//'/'-.^/^'/^/'-/^-'^^^ :^-

:'.-'ALVEY'"NO;" SAf^LD/'cF,'fBAXTER*a,'- GOWER Jc;/kkzANOwsKi: wft'>/.:V?; =7?'LANE PW, LEECH PK, NELDER JA, PAYNE/ RW, PHELFS KM, ROGERS CE,ROSS GJS, SIMPSON HR, TODD AD, TUNNICLIFFE-WILSON G,WEDDERBURN RWM, WHITE RP, WILKINSON GN. (1983) r GENSTAT: A ' _

.general statistical program. Version 4.04 manual. Harpenden, Herts:. Rothamsted Experimental Station. " - i! *

f c **

/AVERY 3W. ,(1964) .The. soils and land use of the district around Aylesbury and. „ _. .,Hemel Hempstead. London: HM Stationery Offic^. (Membirs of die Soil^Survey /...;-.•;' . / :of Great Britain) ^

BARIS YL, ARTVINLJ M. (1982) Natural mineral fiber-induced chest diseases in v

Turkey. Archivum Immunologiae et Therapiae Experimentalis; 30: 161-168 -: ' . " • ; . , -^j - * ~ ^^*^ v ,~ |--BECKETT ST. (1975) The generation and evaluation of UICC asbestos clouds inanimal exposure chambers. Annals of Occupational Hygjene; 18: 187-198 *

BLACKFORD DB, HARRIS GW.'(1978) Field experience widi SIMSLIN n - a j*/continuously recording dust sampling instrument. Annals of Occupational Hygiene;21: 301-313 v - #?* *

BRADLEY A, HADDEN GG,/WESTON P. (1983) Dust formation; in. relation tomining /practice and dist controL. -Mining Engineer; \^2~-. -533—535.-,^538—540.^.•::,~.^.,:^ •.'-....;....:.. :.,

CRAWFORD NP, /THORPE/ HL. (1982) Effects of counting rule packag«!::pn :the :

reproducibility of asbestos fibre counts. In: Proceedings Fourth InternationalColloquium/ on Dust Meastiring Technique and Strategy, Edinburgh. Eondon: ,Asbestos International Association: 45-49 . , .

CRAWFORD NP, COWIE AJ. (1984) Quality control of airborne asbestos, fibrecounts., in die United "Kingdom - die present position. Annals of' OccupationalHygiene; 28: _ 391 -398 -" _ _ ;

DAVIS JMG, BECKETT ST, BOLTON RE, COLLJNGS P f. MZDDLETON^ AP.(1978) //: Mass and number of fibres in the pathogenesis of asbestos-related™ lungdisease in rats. "British Journal of Cancer; 37: 673-688 - - " ' _ -

DEPARTMENT::~'. OF ' THE ENVIRONMENT, INTERDEPT. COMMITTEE ONTHE REDEVELOPMENT OF CONTAMINATED LAND. (1985) Asbestos oncontaminated sites. London: DoE. (ICRL 64/85). '. _ ' -

DUNMORE JH, HAMILTON RJ, SMITH DSG. (1964) / A n instrument for die.samoline • of resoirable dust for subsequent gravimetric assessment. Journal" of

n McCONNOCfflEx -•-=ED.-» WAGNER JC./ (1987)^ Mesodieli

"' -•-76Tiora^^2:>'"^2^M-''!^^^^5S^^®, v-~--. •;.- ;f no1*?,>.. o>**r :i5^^ 'vi^^fcvwif ^»%=s%?^; K-. . .:.i<='-^?£' ^^^

WILLEY.RJ.'; BLACK" W. In 'preparation.

; TABLE. 3.1

Airborne respirabie fibre and dust j concentrations.-•- • : -. '-' • . • • • • ' • • - . . . » • • '~ .»*.'£.. ^£ ..»*<• '•' • . . . ' .generated from/"die 36,tests.

'Concent rat i on. •£; mg m~3/ '.. ..'•.' .'.-::'.."

Fibre/./ ... /;-Concent rat ion'f ml-1" -'/,//

Normalised

Asbestos ; As best os/.'Cone: 94 '•?

Resp"dust

Totaldust /

:TWA TWACRS2

concent rat fori.-/^-;;;?:.. •.:•.-,••..,.' -^ "' -.i;*;**2M**r;5 -;?*•.%*•"?-' *, . . . _ . .•; • . *• . t.—^x*»-»" -..*-. - - * ., •-•,-- •* r — •

fMnr~'1/ingr'm~3X.:&?£:•,'£•?*:,<'-^ ; ;:?#n;"TWA. 2%TWA;. 3^^4' tSl?^:n?u-—-:/'^rRS •'^'''''K^'y^-i-.^^-^^ERM

•Araosite/Clay 0.001- ' . - • •;.• : ' • ; ' ' ' • • . • : • .0 :01 ' "

Amosite/Int

AE30site/San'd' '

.0

.001/0;01H.V '!

i0.

8.7-

T.23.04.'3

-10:''6

A, ,g

8''-''4'

.?••

.2;

.6

.9

.0

;o '.001;oi. i\ :

-J7'

Chrys/Clay/ ' 0''';'y

• Chrys/Int'

00101...

0/11.00.001o.oit:

.9

.5

Chrys/Sand

Croc/Clay"

Croc/Int

Croc/Sand

:o.001.01.1;o.001.01;l.0 ..001.01.1,0.001.01,1',0

;r6.o'•CS'.4'

4.6:/7..8:

:-:.6;5/! 66,

/ 4:5::-:;4.9;

/'3.3. 3.14.06.24.86.4

00295227047

9.0

:715

5.9

•4;0,

;/8\O/

,-./o';i-2'.16;/.o:

1210,. 7;U

4.5'"7'5

-899124564

11•: 578

07:'38,54081432:4712460010070833:;

440608191602

0.211.243.980.180.180.844.580.19029877034331 .30

.07

.10:

.69

.30.10j23.43;36:,14:s6

^:2'-33-19/200.080:17

: 0:42.76.08/i4 ;

u-o,:/0:n o - ,;/6,;/0',/;o.?;-o;12.0o;

5,00

0

''• 4',

0

. . 109001

13'

o0

.'•;•:. 260017011

12:.r obi

21

.28;76.02.24.23.89.-25".23.12.67.19.11.42.17.06.67,77;eo

indicates time weighted average.r-nnoa-i 5ofor;»nr:s Method

N

TABLE• . . • • - . - ; . . . . - . - . :

Average fibre , concentrations (f ml"" 1 ) andaverage normalised fibre concentrations for

asbestos tjrpes in each1 soil , ^(c)all asbestos /types in all soils

/ -"/ Vv--^;'; :'.v •:•'-./" .'./'.v/' "/""::,^/. i;-,. ^V •••"-.••/ . .- - 'C .-; Central Reference Scheme Mediod

Normalised .'.: to 1 mg m~3 respirable dust concentration

Airborne fibre concentration (f ml"1)

Concentration ofasbestos in Soi1

0.001 0.01 0.1 1.0

Asbestos/Soil type

'(a) ' " ' ' Y ;Chrysotile

Amosite

Crocidol i'tc-

C N JL N

0.06 0.01 0.18 0.04 0.98 0.16 6.1 -1::34

0.1 0.03 0.40 0.07 1.15 0.21 12.6 2:0

0.17 0.03 0.67 0.15 1.43 0;2S 13:8 -;2.3r/'

Clay

Intermediate

Sand

0/13 0.02 0.17 0.02 0.74 0.II 6.6 0.85

0.12 0.03, 0:49 0111 0,71 0.15 10.1/ 2vlO:

0.07 0.02 0/59 O;i3 2.il 0.38 15^9 2:93:'

Overall averages 0.11 0.02 0.41 O'.IO 1.19 0.21 10.8 1.96

Average Respirable" Dust and Total Dustconcentrations: achieved for each soil type

So i1 Type Respirabl* dust,: (mg/m3); /./..

Total dust(mg/m3)

Rcsp.dust/total dust

Clay '

Intermediate

Sand

Overal 1 soil

we

: 6.

."!'• 4-..'•" 5"• '. 5.

an

87"

63

10

53,

&t

"... i

';. i

i

i

u , ue

.31"

.34

.22

.61

V . P»

•.;:;'''.;:%.']9

V .''•' v-'5

6

7

r «A » I

.40

.68

.94

.33

':-/i'"'i

i

2

.91

.50

.97

.37"

b

0

YYbi0

;74/'/||

.81 ;

•75-'- '4'..'•'"'• «'> :'"'iii

.T7 " =:|

- v ' -^:;:::" // /TABLE ''" 3.3a ' • / ; ' : ' - , - : '

Respirafale dust concentrations measuredduring sampling period of GCT test

Intermediate

Sand - . - ' • • . .

mg m

0.60

0.71

0.37

-3

'• WY-B-.-S?.

;///•; ;•'/ .'•.;"' a"=:/deviation: frosai^m:due io.;asbestos:.type/^/ .,";//;-/:.:.;:-/;

YP/Y;,/Y:;:-//Y'y^A/^-,///'/::;'.yc-.'/.:: //s;:= deviadbn^ fVbmlm due: to. soil/ tvibe "V/:^r-.--: /.-;- - '" " -

&S:^^::":''VV! -TABLE,. :^5.:;/:Y£Y,. /:

:%|liiEnumeradon/"oiF;;factors ;in.,Log-Hnear ^:: /regression of. "airborne :£-/f .'//-^(see"; Table': *A-'

' ~£.^f£i

m -

/•;.>/Y^:P:3"':;'/.-' - .Chrysotile ,

- ; • /:/ ?^??^:~:^::::-l Croc ido l i t e ;

• ; s/. -. so i 1 ./.type;. -; c lay,,/-;'/ .': -'

c/-" asbestb^/content/^ 0;00171

lfilSISI iiiSPS- - v .-'-'•-' -•. ;,..'• ':.:'. i.'.-^'-yf >•;-. •' 7-.-.'.'.'... .. .. .;••' :>> < «/- v .-'-'•-' -•. ;,..'• ':.:'. i.'.-^'-yf >•;-. •' 7-.-.'.'.'... .. .. .;••' :>> < «/

' - : - ' r "

0.0

-0.61

b;i3

o. o

0.35

:::6;84v

-0.0

+ .'"*+* '.1.3 +

;2.38/

4". 57'

vi •..-mi-,,-:Jvv,---^^-:^C-'-'i . , ... . . „*..-.:.-•--.-;.'-. -^-j *.-.;,;-:".(average) •'-:. •.-.-,•:/.-=-;-'

.-:«•.-• -• -.A; .-:. - ' -£ i * - * • -» • * " - - * . - . - f e - . ' . ' 1

V.lV/rff Amoisi t'e^sand:.'/; // /0.1%' '.// l&^^^- lp©^*

/49.9;

;25.-5. :-_'

V/3 . 73"

48.5 - - . . . / -/5.76. ' :'^/:/:-,-'h-/ ^-:-:--•: '-. '..'::..rv..;j- - .•-1-

:^>>':7-: ^^^K-^ '/V:^;;;^^;7.^^^^,. i.:-.- .--.•-;,:.. ; .;,.:.' -.•-..- .- <-- ..--.. ^~* \ •:•.:::. i.?:.-, - 'r>:- : "**.**-*'"-•

' ^^^^^^S^

. sgchrysoVi;Ve|ci'ay/v/Y/o;i i^;:./^;//;

%£ Croc i dbi;i:'t'e/ ;-:i£:y/:':i -f.,./:: ?/ oP1^l cfIp^«lfp^b:fiM:/- :S^Ss^ lg^ s%^§3^^?s?E*iS?:¥-- s- *f -ii:;*.*i-K • ."-•:

||Slff fgf!T/ : :;5!fY":- ^:

/:;y;y;nt-erme'ciiate/;;':;://;:'n.0.0154/ • • •

: 0.001% ""-"•'/Chrysbt/i/;;,-/i fit erniediat e-^

giui:

/^^^T/;;

0.21

:0.68 :

1. CRS averaged for entire test

0.23

- v

f??Pt£l?i^9MfPf WWi^H / -r^ }&?:££':

•::'^%f.y:/?xXV'>£y-^ '.'•••:f//.'• '-.; . " • ' ' ' ' "*•^^^v/^.^;:;;/^^1'/^'^:/;.•//;:/,;; fo•;.(/".. • •.-//;-/^:,/;::/'•// v'.Cl/." "..;-;

|||§|'SJJIf^&£^~*2:^;/' Y'vYiTABLE;r/:3.7' ''Y//^."/ ':•'

Normalised airborne concentration^;*-• •1-;^--i:-'^;^.';&-:vS<>y,;

'• -K .'•,'. -1'-1—V-''''•^•-.-'•^'G-^vv.

--. --;:^:' ?^:j:5f';s^:*r:-

::;::'l'Vi /•'-,": Amoslte/clay.. 0.001H:

, CRS fibres ml"1/mg m~ 3 ; , , 7•- . : , ; ; V'//".''?' "; ;/:^/

- jest .1 ;/;-:/:Test' 2 -///Test.S^,.;/ v'V^^

0.01 0:01

... ' Average normalised• fibre' conici: V ,(f ml~Vmg m~3):;for dry soils/as: determined

• " • ' • • " • " ' , - •" ' / /v'- in. the GCT tests/'>:"":';"" " ' ' ' • ' '

^^^<3^^^^<J-^"^Y^^^'^'^-'' /'-;//': rf. . .

CLAY

/Crocldbrite r

/Amosite -/' -./.Y'Chrysbt i JV /fo-

0.010:02

/sb.03'., Y/, '0:;02y '<:. r-;/-/.. 0.92;- V.- ' h&,A\-9^£3&$^:\^^mo-,os^^Xo^z^• m^-^mm±: ^•-&:*xm$$8&ffi

" , - • • • ' ", :- -•' - . " , ' " • ' , v.j* ••'•;•..; ,j.:.' - ^ • ••: • • . . ' * • •' • . " / • : . " - '•

i'v'i^ -• ' ..-I-?,— •» -; •"->-''• '/'Jlii-'""•-•"''"' "" '''"• -. • "'• ' •'*£•+?•?•''' ' "''..• '•"'• '•••'•'I--*t? ':.'«" "'',' ":P 'm^si^ij^'lJ^^^l o. oo i %Y:^

/Crocildol i te//£;;/•--•^i'.- '•'-. ---•-••Y-.-T.' '".;.;'ri" rs-.-.-.i:'-.jr-:.'Tv'r-1 Amos i t e-:.i ^:\^-".

o.oi '.-;./•-0.04 :r//0.01 ,S

II ..•.••! .1 _^_—- M-!llln_lIIIIBIKW^ i - BBHMIBBl> _ ^ _ «BB ^ _ HIH_lla HK V _._M^ V. . V /- l ^ ^ .u ^ ^ ^ ,

• - - - . ' • • ' ."•" " ' ' . ' - . ' • ' \'.'.'.'• '• '. ••..-.-.. '.". : • ^ • ' '.",'j"i- Jiia'.'-C™ •iC'i •^•J'^^-'^ ^V-' ''•T^J"'a, ' '-. . . • : : - - . .* ..-.. . -'• *-; - • • - • > . • • . . : • . . ' * . , . .*-. .1 .. .*•••"::. ..-.-f-tr* ^ptRrJsS..•*-••-...- ;n ^*

Croc i do lite -:

Amosite ./'.V.'.":Chrysotile..

Ir^S^S^-S^:/:^/-./'- /^-//S''/^^/^'''^/^-^^) each/:;asbestos -.:?;^7m/;ail/soils/U|if£i$:'; S^

I C1 • - ' . " ; ' ' . ' - . . . ', ... '. ' "? :" • • • • ' . . " ' " - ; . . - ' '•'?•:. :';,'."J_.j". ;•:--' '.-:.'•::'-::..'... -V.: . '::, '. ' '" .'- • :.'- -.".:.-.. .'^ '/ /MLI/ CTJ ' I UATTT/TJkT "'.'.. " . -I .'•'•'-"'•!:. ,X;-'- .•*«.. •."•';--.'i'.."•..••' :.,liX • • • • ' • • . •'••*•'':*'-"•.>' •...I.',1'..'.".'"-1'-'.^*. . • " . • . -•" - ..-A'V-.';•-;•'- CUrit.rJ« 1XA1 lUN :- - _ . _ .

|»s A":t-r'"'J:f'.'r'i.:'''r'"i'1-'-;''--'A>'"!'v~":.:';..''?*".: ••••'•"''^v-S:r^ir:-':"1";-'-.c'-. .;y"'"':^-'. -.; ' . :.^'~'^'"^-" ;v.;-:-- •'-•:'V'';-r.'l;>:"T;-:;'::.'»: ; . . • . - - -^vK7-:^;:.:/' "•>. iv..'. (a)': - ;.^'; /-';'::,

;;:'//^:.1 '0.001M .'.///;.:.^0.01H;./-/:/:. .;0.. 1H"';;

r"'Y^S'-^"^' Chrysbt i I'es? //^l^^fe//// ..- ' -Amosite :/,;./'.':•'//|/^^-;-/;. v-^g: croci d'o ll t c '"•''•: *!.i

/.'•: i 0.02-.:///- 0.04

v 0;09V

"6vl«

'b;020.030.040.17.

;.o..39'0'.310.86:

^TSSSSi®: !

U///.-K':

^ftiE^iV'.'?!.i'« •'•"-•-?'«-"$•&••'. '••::''.~:

""''

- ';WET_;:f|:Sg^.^r;f /Pi: OM //^;-

-Chrysbt i le/in/Clay/ / •'.; '-";/-. " "

50 '';' /Yr;*;YY'>;-^/3.:/nd '/:/ ' =" 'M n : '•'.'•.•'''""'".*.'•. • ': ' ' . • ' ; - . . ' , . . . .'.'J. -40.-.. ^5. :...-.. r;.:. .-.•-•.:-•.;."•, '..:nd •••30.' //v:,^'/" ///'-.'-":•:-' " :nd':" ' .- ' ' • • ' . •

•20:-.;-v;:^.://." ;'/;-;-' ./;•«•" nd/r:. - • / . :'10 :-.-/-/;^./'//, cu/ .;///;'0;62'.- ' : . - ' •

5 ,.: ;••:-:/?' / / • . . • / ; / • - . : .•:.';.;0.04-- • ' • • ' . • ' • /0-.-:^v^// - , " • ' ' . ' . ' . ;//l:.27/ ,. .'/-

^•''o?™/

•~- Tlu

. ' ' ' ' rzd ,./ nd"/.

' . nd. ,nd

V 0.02'-:'• 0.07

: v " v|°'- °-^,/; •• i : '". ° -

'^''I^'^J^:^^^^

' -:'"/'"' /nd:-::-'".." .'.' '. '-''nd-'^^ff^--:/;/" . , -j'nd : /•_,: ^/-v..;. '-. .nd/; ;;:. ;;::;:

'' '" . .; -:'"nd' ' " ' . ' ' ' ' ' ' ' ' nd/'t/i/'-./O .;/.,;• nd ." '• ..;.*: nd •" '"'•''•."'• -;

' /.nd' ;./ ^ nd ,^. //•.; •;0.03 _; ; • ; : .__- '/'-'0;;o2/.:>YV;./;

Chrysotile in Intermediate

5040.30'20,10'5

.. nd--.nd."ndnd -nd0.16'o.24

Chrysotile in Sand

- . 40".3020/

• 10 ^•S-.-

• ' O . -

r ; v " • nd: - not : detected

"ndnd.' .nd :

'0.020.04"

ndndndndnd0.010.06

nd " '-:hd.:./"lnd

%nd: /nd //;

0.03 "

:- ..-.-•-... ..->-. •• *i*SA.v?'Kj-v.-v>r- -•-..-V'1=?«: '3: ^S5*iJgS£^M^•• iS^^P^25^S

5040

.•'••: 30"'*'•• 20

10

ndnd ;.: ,'nd /. '•/- ••'. .'".0.01 /0.500.432.46

nd: -, ,-• nd' 'X • nd

'••"" nd0.010 . 030.52

••'"nd/ . nd

.hdndnd "nd

- 0:06

•• Amosite in1 Sand ;

" 5 0 /. / '

"/SO/ '- / ;//, / /'

' ' •• i f . . ' • :••• : ' • ' ' • /;."/o / . . ' _ . / . .-

nd - not detected

nd0.010.04

;0.070.060:115.08

ndnd

0.010.010.83

nd/nd:

-nd..

-:.Croc ido 1 ite_<iri;"C1 ay; :- ..///.•••

;2p••'"••."-,vA' :V-ib .... .//^/.;

"rid

" 0:94:

Crocidolite in Intermediate

40:3020..

.-"- nd "i"'-• -,nd

, ' nd ./-/hd:'/

•"•••"/0.58 •

Croc i do I i t e . in Sand... .•T'sTf'.y, -; 4s/:/-^Y'i":- :\J-/:v^:;/;:.-^^/

20-"' "-10.:-

5'• ..' .;"•'

//:/:nd///

' './'.-rid"/ nd.

':-'"•''.; :'.-r.:56'

-' not de't'ect'ed:.'

/nd; ,;

" rid0.020.03;0.07 •'.•• o.oi

rid //

0.01

?-;'/.i/;^;-;f.- -'4/:; ;;.,;• nv^^

• ' ' ' ' '

ndndndnd-. / .nd ; - - '0.030.09

ndndnd

.ridnd

ndnd:nd

. nd

='.-- • -.-•• f-1ii:r'*ns-ii1i'.'3£S,44!--B,- ••»*'• ' >-Vi

^ :/ : i K^w- .... :" - ^SfegS;MTii ;i:J:4

ridridndnd /

0:10""

• rid

,: ' •"•;•.'.•: = ••••.;-'; .>;-«.-:r- i';-^Vc-. -;*-ii;; . '• ^'''-•^^^^S^fi?^,•• -'-• •**» -;" -_•;.' . .'£.." *".;'"'.'^?VB"i v^.'-":'..5J-* '"^C**

agfter ^SSS

;.;. FIGURE'./2'/.-lExampIe of airborne, fibre/ebncttvariation/with^ tirnre (100% wet soil;; 2g:/"charge; ,GC

fibres M!-1

0.08

0.06

0.04

O.02

0.01

0.08

0.06

0.04

/•-'/.'•; .-• 0.02.

^•VSu?^/'/^'.•' V" vr.ti-' ---"i1 ••?-' '•:-.v:';:-> '1»<">foVJ'..' '--j. j

•::/-1-vv:-::/'>r'7'^''^:M' , ;'. , .". V '•', 5 M>*.-'Il

1 •"" ' ' '" i','ji * ' •"•: -' ••'' ?'-'1

_JL

0.5 : '.£..: ;l;5 /g;

".-".'.7,-: • .-•. •!i..;7:-"' ~' .V-"?'.tfssr>..-'"-,.:'. :;."•''" ••V'.si'.-'.H'wL^^'iSS

-sii &i»^i;i;S- "j'---'-':i'S i? i:J- ' ' '' ' r'-'•"•" ;-:' -i: -it,*-.;"-i;-':.''.*":*".*•*• .JT-JM?';-*^J'i'""i!

r.,..«...... „ /v. .. ,-^-j -.. - V.f**J;.ii..;;.:.-,-i7U.-i,-V^f'^«j5ifctft:i:'

.- :-: ^Kr^;i; *®^ '-^Ifei5&?^::;;vtl <h ); o; -;;;:|3gg^

rSISS

:•> ,-.- ..: '/'fr^r^S^Sj-*"^

. -1-" !:'iv '-" ---*;":e|- -^•.'••'••'•'••''-': :.V- ':fliS'i-^

IMt^y/v^Y: ^:/:/.'::''' YY 1 of'ssbestca/'iiiv'sbii; 'average:,results 'frbn^:^fef^f •{;•;•>':/i?*^' yYoi^.:'"^/';///%':;Y;: '• • :/'"' //•-'/-'Y'^'-:-:;/ " •

||lp|5||S!f-l-;;;Y':;^

?v'_'r^""/''. ''•'.'. :'"*.".''• ' -.'""* ' *. '-'.>""X '' "' ':; - r:.^-. . ' / ' • • • •' ' '•'•'•:-.•:'.'". • <-'. • '- ,'T '•'' --">' '.'.*:?i:-.v-'r. • * ' ' ' ' •' ' - • ^.i^i'&A^'^':i'-'.''-'• ''' "*V" /:"''»;r"i"/*'r*^r'1'.•;.'%". l-'V'.W*^*

'?••>• jf«^ • -•-

fiSBESTDS

/CROCIDOLITEvAM6siTE;;: /:-Y/CHRYSof ILE

D.DDb e s: T o

>J&?4!»;«' qonc^tir/atlona;/.-/•

• • : • ' ' >;;;<K^ " i/?•''•'.''ifcY"- ' '-'f^W^.4^&M'^^i^^^'•'•:•"• *\</;^*v.:.:<,!.•'• ":<v/4 ::.-VftV]:^v>•/• -a-* •'.;•'-::•-£•'.•• •&. <:&*£&;•'••-..-:/:•-a/;--:.•.-..•'•:•;•,&:';.-:•"... - , " n:•:.:<•" - • • ; -^,1^:^^ry** • v:. .'•*',,;>• 'ip^^ll^^f

• /;. v^rtK?:^ ••'••.-;: ^.;:y,?-;---. ;;."5.>:. -• .v*?^' :'•:;;•--; V " - • •^••-:^.-'.-.: .S""•'.-•-•;•?: .^•;->U.J«i• ,; " •-• ...i;:^:..;,; •. | > l.'^-.."-.^^ ..,;•,-])''•:' SJ i |:'i.

:/::!i!S ^^'!^^-i:^'^./-''-.^s-H^./.::r:':.L-^ ...:-/?fi;y • • - . . . v //•.,/;-.%•; /^;;.-:' •"-;t';v'-f^*.iM^! < • : ;vr"/.v;/-/:i/:/:::^--:.^":!n://';'K^:^ /.":...'.^-:- .-/.••., -••.^:r^/'-i'/^/>-v'---'.^^:^:MfeiM/.'/.^•^•^.^•''I'^^W.ti!Wffi$^$^.:0V^:^]^'^:^"• •• -/.¥-. / ' • :;..^€^'0>'- ;;;:V:/|<.np^Y,;:/ ^5;:^^?^i^^f^ -/^/:/^/K "• : ' -"-"" • • • • •--"*•'• ";: d!ipS^Si Y .: ''/^'s :^^^feU':^fofrvabtiLE'-i--'^ ' : ' - ! ^ 1D?0if~ •"': . / '" '" '--•——i/v-'-'1- '"•••• : . v"•"••"

j-rr'iMtrwttTi'Tr.''-•'•"-'i";1' .;-v'::vv..;:':':i-'if.; ' .-:a|iY : ' '7.i ; | 'V ! '-:i :

:: ' '•;.••-.•••:•':,•.! '••••; '• '••' ' ' '•

o.. i;

0,111' ' * '

(n ••*;•'.>: .-••••'•'.-

•fer•'BP:-'--.^,'.' •;-:.a.iJ

•v<

D.OtJ

.. .^ri.-.-.;:

C ':;f:;';'

-^•|^'^'.--';.-'-;-XnMOaiTE:—v:iHitweDiATr.il ' , • / • / '• ' ;• •;•',;'ctiy"" '"•/•' i '-'. ';•." • ' /-;.v

/_///>Xf^;"-v--,/.;r::"/'•: /:/:

oiy-w."b:i

; i.o'-?.-•>^o.,

p. ot

I AW

—• IHTtMCOlATC— CtAY'

••.'.".v^-A :r-i:;::/-... -ij^" • .,. ••-. •:-i^.-^'%-J•/- . / . ,<; ' • • - • • ' ' • i - - ; < • • V - ' v / . ^ ; ;V--:"w'.%-5^• - . • ' • __•• .:•• y - . - - -.- ; •i;-.:iKi;v;;

l"|CfOCIDOUlTE

S •//

0.1X11 D.OI j :" Oil ' " ^ ;.:.;•>«'VI-^A-^J>;- ..•«'.,.• ••?•- :••

•' ^MS^^^^^^K^^^:t^xsiim^^i&i&f^m^in^-Y' ''^iK^'^^ ' : • -:-::'„'•*"'. ] • • ' ' • '•' ';/.':V* i V i ' V :- , ' . . : ' • . * ' . ' ( • - • ' • • -'•>:.*•,•'•''• * '"./':.' '..'--'ti'. ' •'•:.''.*'••: :.i;'''•'•* -''.J-'i'" : : " • ' " ' •" . ' • " .- '

.-'.-."jr..1 ;Y-SvH:;VH./f////. ••-r-^:'Uy;^0%/%//|7:;.^/'^r/:i:>:/-,' '$«... - , . ; • . . - .

'•";; '%%$•$$$•$$$& '^^•l^^^-iS^^^^^-^^-'' "-1 ^^-^^' • • ' V - : - : • ' / ' ',. • • ' • ::"-;,lT$. !$^^ /•;/'-.•:-.•:, ? . . ; - - . . - "..- - ..- , : - : . ; . - , . ,: : , . . . - . - • ,jfc-fl H' X

i; llpiiiiaiBiii'•?/::• ;:r^w*^fe^^-^^^ . v = > : : , ,- -,-.->?v/y . ; • ? • - , - . - . ..;,.; s.,: - / -.:-.;,,.•••• :.u".*;.>-;v--s*^

.-v.-X^-S

.• fe'/:

S:-

ii:V-AS;.:,

i-^ei^telllil.

f*Jt •*'

•y • . . : : . - ; • - ' . ;/, ;;.:.;;> - i , . ;-!.';: --3. ~- -"7 . - := . -~ • ~ * - r ' - s : » r r f ~ * **"•*•«.;* *""j vuncenirationa - • -\ :••/• - ' • • • > : .-:i- ••••• i i 'y. » •»

:/"":-;•:/,//:/-// I*:*V"r^£'!«"•^•"r^n-Delationvto) talk:"aabeiitoB content for each of trie •• .-'-' - -^"' '&rt.&W-"-&*4vi://;:'/Uv/H'S^::-^iM^atoB:varietiea^In;.«i?. three/apila;:/;•/ : :- .V/U;^ y/:/1/// ;'-! 7' ' ::. " -- . • :-/.r.i^^^^^Zs&^ffi

:"i^;--o;"-:i;r'1-:".^-'-:.-:: /^v/>; -r ':.i: v'i^^cKiSi-fc^-.v^v-• "•Hfr^SH^-^vi^K^ -' /?;;.:•: ; ;_' ' ••-•."--•';/-' ' '"" '••'.":K"" •'i:>/'^1-^^Hfe-:^^'';c;V:f:•:' •-•• .y^y^^-'K^ffl-^ •£•//;: >i,--;.->'>v/' ;:ri:-:J,^"^M'%':-; ••i-^v-" ^V.^;^^^^/:^!^?' . ;-:-/y.?-: C ':-^;.;-..^.. ' - -. •/ '., '''r^-..^^^ --^:^^\

^_ roviaN <trm <ui , : • ! • - • - - I " - - *"-fVT i "'"'' ••%'•'»«._._ " • • ' • ' ' ' - ' • ' - ' • • ' - ' ' - • ' . - ~ .' " . , v l ' - ' •" . '

W€^SfilC'^f^Yfi'.;' ::;'ti -

in soilTjV*";i:i;!f!:J-!-|:''.'.'f. •,•>,'.':. : • : ..- :".'.'.•.:

CTOCloaiTE IMTEBMEDIRTE— AMMITt ' • • /'•: •-'••._ -.':.; ;

- -I., CHRYJOl IU //. : y;y-(- j / :..'-:

r— WOCIWHU BOND--• AMOSIU

O.O01; 0.01 0.1

' - X Aabeatoa in soilp.po

% Aabeatoa in aoil

• • • • • " - ,-vy ; .::•.-.-':.:.. vy..-4 ^-,;"::•>' -:/:4-':/.'; :V; .P/;.- '".' .:!;' '. ;'

• :' .:V'.";:': "'•;•;'i' -.*:..-•..••:. '• '• •:;t'::wj.",.•:;':. :-':;:», .•> :-.; -f.-.-...- - "'v V. ..-. 5: /j,

- 'i/' '"^-.//'?;'.'• -"'v'r.^'-i'-S•-.:.-;-:• ••;•:-:: -.'. -'^. .' .feV'X'V. -• • ,i.:;'i"ft«.-,'.:, ...;--^>'-'.>.-'r. v;/^ •";l"ifoe?i«*^-

• ^- \ r .<! ; . - - ' : i - . . ' ;•-.•.-«i.4 if ' ;:k4.-:j.''V'!• • . • - - ' .•::Vo'Aii i,-.:i--:U':c.:•?:•..?£ ••:.••'v*^;5feft*f

' - _ " ' " .' "*7"lf^*" v- _;n'.. • .;„.- - a -• '

FIGURE. 8/ '.SIMSLIN dust monitor voltages recorded" throughout/ . ,.;r: •../«:/: :^f^Jf?£

a series of tests run:.with HankTsoiJs. Voltages are proportional to respirable.-/."ip'^vivll^Sf?"diat cbncehtriations. ^=The direct relationship y ' - ' ••"•'•'•• ., ,/'/;/;/::.-'i'-!i-depends. ori: the size distribution of the dust -• • ^ - ' : y . - . ' ;:-/;:• -*$• '''•-

_l • --" .j.'.--' .":J*7'.»"-^i'vo; JV-•..:-:-'_15.: ••rt%' :•':'?

(a) Clay

5 2»J ••g 11 VOLT '1.2' Jo-» respirable

TIME (Hours)

(b) Clay

.. • v • . - i ; . . . • •. . -.i .^.•..'•iiw.-.-.' .v.:^.*..

(c) Znter-- mediate g 6

, 54-

(d) Sand

lijagfe^sftfe^&g

49 • • • •- • • ;•-"•: '. -r*s.t «*:'.;.3i»tt£

' " //-yte;iiifIiBj• :. •*'•:. /.-•-...'>,.V5i'l.-.'vA*^W^%il

: • • .r... .f.'.-: ; t».t.- t. . :-.

PLATE 2 Clay particles entangled in a bundle ofchrysotile fibres in airborne dust from Clay/Carysotile

1% mixture. (SEM X4500 magnification).

-.••t i*:/-•1 •' -.' ' "';" • • • ... • :' '~*^:C-

vm

50

PLATE 3 Amosite fibres in airborne dust fromSand/Amosite 1% mixture. The.fibres are practically

free from adhering particles. (SEM XI800 magnification).

"•3$t:?£!l